Restoration & Preservation Enterprises in Kankakee, IL, handles window renovation projects around the country, some running hundreds of pieces. Many of these registered historic sites require precisely machined re-creations of the original wood moulding from antique wood window brick frames.

To accomplish this, owner Ray Drazen has adapted a process for digitizing the original wood brick frame profiles, then converting this to a file template from which he produces his own moulder cutting tools in house.

Restoration & Preservation specializes in making precisely machined re-creations of mouldings and doors.

âA minimum of three custom knives and two CNC router bits are needed for every project,â says Drazen. âHowever we have needed over 12 sets of knives for some projects due to moulding variations from floor to floor in the buildings we work on. By having the ability to grind our own knives it not only produces a better end product â because we can sharpen periodically over the course of a run â but it allows us a quicker turnaround time on our product. The more we can do, or rather the more self-sufficient we are, aids us in controlling the end product and lead times.â

Using the digital approach improves the precision of the process, develops more exact knives and reduces labor cost as well, he adds.

âIf it is an existing wood frame, we start by removing an 1/8-inch slice of the moulding profile, which we then scan into the computer,â says Drazen. âWith the image imported into the computer, we refine it until it matches the profile exactly.â Alternatively, he says he can sketch the profile by hand and scan that image in or take it from architectâs drawings.

Drazen uses a Tem Tech to cut a template based on the scanned slice of wood, sketch or drawing of the profile. Template Cut Shop software allows the image to be rastered, which outlines the profile of the moulding. (It can also import files directly from a CAD drawings.) This file will be converted to G-code to drive the CNC moulder after the drawing is trued up to the profile, Drazen says.

The next step is to establish the offset of the cut and create the template. The template will guide the tool-cutting system or grinder as it cuts the tool from the knife stock blank, similar to cutting a house key from a blank.

âIf it is a 5-inch profile, I go with 5.5-inch template, which gives us the ability to adjust the knife in and out.â

From the template, Drazen uses an SCM profile grinder to cut the tools, starting from various sized blanks. âIn choosing a knife stock, Iâll select from 1.75-inch to 2.25-inch, depending on the depth of profile and width of the board weâre cutting in the moulder,â he says. âWhen you are choosing the knife stock, you should also make sure it is thick enough so you can get several sharpenings on it.â

After cutting the knife stock to the width of the template, Drazen says, âthen I put them on a tip scale to balance the knife stock and ensure the knives are equal in weight.â He then makes small cuts in the backside of the tooling steel of the knives as he adjusts them.

âThe closer and more balanced the knives are, the better the finish. You avoid getting hop, chatter and knife marks from being out of balance as the blades rotate in the moulder,â Drazen says.

The blanks or knife stock are ground within 0.015 thousandth of an inch of the template during the roughing cut on the profile grinder. The roughing cut, Drazen explains, is where you remove most of the steel from the knife stock as you follow the template of the profile.

âYou are just ahead of where you need to be,â Drazen adds. He cuts that in three steps â dressing the cutting wheel and cutting away 0.007 thousandth of an inch, then regrinds it at a slower feed to remove another 0.007 thousandth of an inch.

âWhen you are doing finish cuts, you use a constant fluid movement,â he explains. At this point there is 0.001 thousandth of an inch remaining to be cut away from the blade.

âWhen we go to get our final cut, the coolant on the machine is shut off and the grinding wheel is dressed. That finish cut is called your âsparkingâ â that is when the actual sharpening occurs. The sparking is what really polishes the knife and gives it a sharp, clean surface.â

As a last step, Drazen says he lays the knife on the original piece of moulding to see if they match.

âIn our case, if you can see any light between the knife and the original moulding, we do it all over again until itâs perfect. Before we begin grinding the knife, we also do the same check with the template to the moulding. There is no reason to waste the grinding time and labor if the template is not perfect first.â

Bill Esler is Associate Publisher of the Interiors Division of Vance Publishing and Editor-in-Chief of CWB magazine.

Have something to say? Share your thoughts with us in the comments below.

Bill's background includes more than 10 years in print manufacturing management, followed by more than 30 years in business reporting on industrial manufacturing in the forest products industries, including printing and packaging at American Printer (Features Editor) and Graphic Arts Monthly (Editor in Chief) magazines; and in secondary wood manufacturing for WoodworkingNetwork.com (Editorial Director).

In addition to his work as a journalist, Bill avidly supports efforts to expand and improve educational opportunities in the manufacturing sectors, including 10 years on the advisory board of the Print & Graphics Scholarship Foundation; six years with the U.S. WoodLinks educational organization; and currently with the Woodwork Career Alliance Education Committee, which supports educator scholarships, and develops high school and secondary school curricula in concert with efforts to certify manufacturing professionals skills standards. He is also on the Industry Advisory Board of the Greater West Town Training Partnership Woodworking Program, which has trained and place more than 950 adults in industrial in wood manufacturing careers through its award-winning grant-funded training program.

Bill volunteers for Foinse Research Station, a biological field station located at the heart of the Marble Arch Caves Global Geopark in North West Ireland. Foinse Research Station is focused on providing a platform for third level and university level research in forests, woodlands, blanket bogs, geology, archaeology, speleology and hydrology. Foisne is one of more than 1,200 biological field stations around the globe and one of more than 200 members of the Organization of Biological Field Stations.